JP4854217B2 - Multicolor display element - Google Patents

Multicolor display element Download PDF

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JP4854217B2
JP4854217B2 JP2005140861A JP2005140861A JP4854217B2 JP 4854217 B2 JP4854217 B2 JP 4854217B2 JP 2005140861 A JP2005140861 A JP 2005140861A JP 2005140861 A JP2005140861 A JP 2005140861A JP 4854217 B2 JP4854217 B2 JP 4854217B2
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display
electrochromic
color
display element
electrode
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JP2006106669A (en
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拓司 加藤
伊久衞 川島
成伸 平野
毅 渋谷
裕幸 高橋
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株式会社リコー
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    • GPHYSICS
    • G02OPTICS
    • G02FDEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00Function characteristic
    • G02F2203/34Colour display without the use of colour mosaic filters

Description

  The present invention relates to a multicolor display element.

In recent years, electronic paper has been actively developed as an electronic medium replacing paper. The characteristics necessary for electronic paper compared to conventional displays such as CRTs and liquid crystal displays are reflective display elements, high white reflectance and high contrast ratio, high-definition display, display In other words, it has a memory effect, can be driven at a low voltage, is thin and light, and is inexpensive. In particular, the white reflectance / contrast ratio equivalent to that of paper is required as display characteristics. It is not easy to develop a display device having these characteristics, and it is very difficult to perform multicolor display.
Examples of electronic paper technologies that have been proposed so far include reflective liquid crystal elements, electrophoretic elements, toner electrophoretic elements, etc., all of which have a low white reflectance and are capable of multicolor display. A color filter must be provided. Since the color filter absorbs light by itself, the reflected light is dimmed. Furthermore, since one pixel is divided into red (R), green (G), and blue (B), the reflectance of the element is drastically reduced. End up. Therefore, visibility is very bad.

  Electrochromism is a phenomenon in which a reversible color change or a reversible color change occurs when a voltage is applied. An EC display element using the coloring / decoloring of an electrochromic (hereinafter sometimes abbreviated as EC) compound that causes such a phenomenon is a reflective display element, has a memory effect, and has a low voltage. Since it can be driven, it has been widely researched and developed from materials development to device design as a candidate for electronic paper. Moreover, since various colors can be developed depending on the material structure, it is also expected as a multicolor display element.

As an example of multicolor display using an electrochromic multicolor display element, for example, Patent Document 1 discloses a multicolor display element in which a plurality of types of electrochromic compounds are bonded to a polymer. In this document, an example is described in which an electrochromic compound that develops color by an oxidation reaction and an electrochromic compound that develops color by a reduction reaction are bound to a polymer. In this case, only one of the electrochromic compounds is colored. However, the two types cannot be colored simultaneously.
Patent Document 2 discloses a method of performing multicolor display by combining an electrochromic compound and an electrophoretic element. In the method described in Patent Document 2, three primary colors can be displayed, but full color display is impossible because they cannot be stacked and mixed.
Further, Patent Document 3 discloses an element that performs multicolor display by laminating a plurality of types of electrochromic compounds in order of increasing or decreasing threshold potential for forming a colored state. However, full color display is impossible because each electrochromic compound cannot be individually developed with only the threshold potential for achieving the colored state. Further, this document does not describe a specific example of this element.

Japanese Patent Publication No. 1-339086 JP-A-10-161161 JP 2003-121883 A

  Accordingly, an object of the present invention is to provide a multicolor display element capable of easily changing the hue in view of the above prior art.

The above-mentioned problem is provided by (1) “display electrode of the present invention, a counter electrode provided to face the display electrode at a distance, and an electrolyte disposed between the two electrodes. A display layer formed by laminating two or more types of electrochromic compositions that develop different colors on the surface on the counter electrode side and have different charge amounts (mC / cm 2 ) for developing a sufficient color density a multicolor display element having,
The multi-color display element, wherein the two or more types of electrochromic compositions are conductive or semiconductive fine particles whose conductive characteristics are changed by attaching organic electrochromic compounds that develop different colors to the surface. "
(2) “A display electrode, a counter electrode provided opposite to the display electrode at a distance from each other, and an electrolyte disposed between the two electrodes, and different on the surface of the display electrode on the counter electrode side At least one of a threshold voltage for developing a color and a colored state, a threshold voltage for entering a decolored state, or a necessary charge amount (mC / cm 2 ) for developing a sufficient color density It has a display layer formed by laminating two or more different types of electrochromic compositions,
Two or more types of electrochromic compositions E1, E2,... En (where n is the number of types of electrochromic compositions) that develop different colors have a threshold voltage of | Vc ( E1) |> | Vc (E2) |>...> | Vc (En) |, the required charge amount Qc for color development to a sufficient color density is | Qc (E1) | <| Qc (E2) | <... <| Qc (En) |
(3) “A display electrode, a counter electrode provided opposite to the display electrode with a space therebetween, and an electrolyte disposed between the two electrodes, and the surface of the display electrode on the counter electrode side is different. At least one of a threshold voltage for developing a color and a colored state, a threshold voltage for entering a decolored state, or a necessary charge amount (mC / cm 2 ) for developing a sufficient color density It has a display layer formed by laminating two or more different types of electrochromic compositions,
Two or more types of electrochromic compositions E1, E2,..., En (n is the number of types of electrochromic compositions) that develop different colors are set to Vc (E1) , Vc (E2),... Vc (En), where Vd (E1), Vd (E2),... Vd (En) are Vc (E1)> Vc (E2)>..> Vc (En)> Vd (En)>..> Vd (E2)> Vd (E1), a multicolor display element characterized by being a combination "
(4) “The multicolor display element according to any one of (1) to (3) above, which includes three types of electrochromic compositions for coloring yellow, magenta, and cyan”;
(5) The reflective multi-layer according to any one of ( 2 ) to (4), wherein the electrochromic composition comprises conductive or semiconductive fine particles carrying an organic electrochromic compound. Color display element ",
(6) The above (5), wherein a plurality of types of electrochromic compositions each carrying an organic electrochromic compound that develops different colors on conductive or semiconductive fine particles having different conductive properties are laminated. Reflective type multicolor display element according to item ",
(7) “Reflective multicolor display element according to item (6), wherein conductive or semiconductive fine particles whose conductive properties are changed by attaching an organic electrochemical compound to the surface” are used. ,
(8) "The multicolor display element according to any one of (1) to (7), wherein the display layer is formed in an arbitrary pattern",
(9) "The multicolor display element according to any one of (1) to (8) above, wherein a white reflective layer is provided between a display electrode having a display layer and a counter electrode" ,
(10) "The display element according to any one of (1) to (9) above, wherein the electrolyte contains fine pigment particles",
(11) The multicolor display element according to any one of (1) to (10), wherein a drive element is formed on the display electrode substrate or the counter electrode substrate. Is achieved.

That is, according to the present invention , different colors are developed, and the threshold voltage for entering a colored state, the threshold voltage for entering a decolored state, or the necessary charge amount for developing a sufficient color density or sufficient decoloring by having a display layer formed by the product layer at least either two or more different electrochromic composition of the charge required amount to the voltage applied to display a plurality of colors depending on the amount of charge And a multicolor display element can be provided.
The display of color development of different colors, and to the electrochromic composition required charge amount is different of two or more to color development in the threshold voltage and a sufficient color density to become colored state formed by the product layer By having a layer, a plurality of colors can be displayed according to the applied voltage and charge amount, and a multicolor display element can be provided.
Also, to develop the different colors, and has a display layer formed by the product layer the threshold voltage of the two or more different electrochromic composition to become a threshold voltage and decolored state to become a colored state Thus, a plurality of colors can be displayed according to the applied voltage, and a multicolor display element can be provided.
Also, to develop the different colors, and a display layer formed by the product layer the charge required amount to the threshold voltage and a sufficiently decoloring two or more different electrochromic composition to become colored state By having it, a plurality of colors can be displayed according to the applied voltage and the amount of charge, and a multicolor display element can be provided.
Also, to develop the different colors, and a sufficient color density for coloring in charge required amount and sufficiently necessary charge amount for decoloring two or more different electrochromic composition with a product layer formed By having the display layer, a plurality of colors can be displayed according to the applied voltage and charge amount, and a multicolor display element can be provided.
Also, Lee yellow, by using magenta, cyan three to color each of the electrochromic compositions, it is possible to provide a full color display device.
Further, elect runner electrochromic composition from that comprising an organic electrochromic compound carrying a conductive or semi-conductive fine particles, a different color and color development, and to become a threshold voltage or decolored state to become a colored state Two or more types of electrochromic compositions differing in at least one of a necessary charge amount for developing a color to a threshold voltage or a sufficient color density or a necessary charge amount for sufficiently erasing can be produced.
In addition , by using a method that modifies the particle surface as a method of changing the conductive properties of the conductive or semiconductive fine particles, the conductive properties of the particles can be easily controlled, and the threshold voltage or decoloring state for achieving a colored state. It is possible to easily produce electrochromic compositions having different threshold voltages.
Also, by table示層is formed in an arbitrary pattern, it is possible to provide a multicolor display element capable of displaying a high-definition picture quality.
Further, by providing the white reflective layer between the display electrode and the counter electrode having a table示層, it is possible to provide a reflective multicolor display element having a high white reflectivity.
Further, by providing the pigment particles in the electrodeposition Kaishitsu, it is possible to provide a reflective multicolor display element can be driven at a low voltage.
Further, the multicolor display element by forming a driving dynamic element can be driven actively, a large area can correspond to the high-definition display.

  According to the present invention, it is possible to provide a multicolor display element capable of easily developing a plurality of colors.

The multicolor display element of the present invention is characterized by comprising a display electrode, a counter electrode provided facing the display electrode at a distance, and an electrolyte disposed between the two electrodes. A different color is developed on the surface on the counter electrode side, and the threshold voltage for entering the colored state or the threshold voltage for entering the decolored state or the necessary charge amount for developing the color to a sufficient color density or sufficient decoloring And having a display layer formed by laminating or mixing two or more types of electrochromic compositions that differ in at least one of the necessary charge amounts.
When a plurality of colors are to be displayed, it is necessary to laminate or mix a plurality of types of electrochromic compositions, and to individually develop and decolor each composition. In this case, it is not sufficient to prepare a plurality of types of electrochromic compositions having different colors. Multiple types of electrochromic compositions with different threshold voltage for color development, threshold voltage for color erasure, required charge for sufficient color density, and different charge for sufficient color erasure Each electrochromic composition must be individually controlled by the applied voltage and the applied charge amount.

One feature of the multicolor display element of the present invention is that two or more types of electrochromic devices that develop different colors and have different threshold voltages for achieving a colored state and different charge amounts necessary for developing a sufficient color density. It has a display layer formed by laminating or mixing chromic compositions. Furthermore, if each of these electrochromic compositions has a combination that requires a smaller amount of charge to develop a sufficient color density as the absolute value of the color development threshold voltage is larger, each electrochromic composition is colored independently. Can be made. An example of the multicolor display method is shown below.
The display layer has a structure in which an electrochromic composition A having a high color development threshold voltage and a small necessary charge amount and an electrochromic composition B having a low color development threshold voltage and a large necessary charge amount are stacked on the display electrode. is there. When a voltage not lower than the coloring threshold voltage of the electrochromic composition B and lower than the coloring threshold voltage of the electrochromic composition A is applied to the display layer, only the electrochromic composition B develops color. Further, when a voltage equal to or higher than the coloring threshold voltage of the electrochromic composition A is applied for a short time, the electrochromic composition A develops color. At this time, since the electrochromic composition B requires a large amount of charge, it hardly develops color even when a voltage higher than the color development threshold voltage is applied. Therefore, the electrochromic compositions A and B can be developed independently. Furthermore, if both the electrochromic compositions A and B are colored, the mixed color of the electrochromic compositions A and B can be displayed.
The above is an example of a multicolor display method using two types of electrochromic compositions, but multicolor display can be performed by the same method even in the case of three or more types. In particular, if three types of electrochromic compositions that are yellow, magenta, and cyan are used in a colored state, full color display is possible.

Another feature of the multicolor display element of the present invention is that two or more types of electrochromic compositions that develop different colors and have different threshold voltages for entering a colored state and threshold voltages for entering a decolored state, respectively. And having a display layer formed by stacking or mixing objects. Furthermore, as these electrochromic compositions have higher color development threshold voltages Vc (E1), Vc (E2),... As shown in the examples of FIGS. 2 and 3, the decoloring threshold voltage Vd (E1), If the combination of Vd (E2),... Is low, each electrochromic composition can be developed independently. An example of the multicolor display method is shown below.
As a display layer, an electrochromic composition E1 having a coloring threshold voltage Vc (E1) and a decoloring threshold voltage Vd (E1) on the display electrode, a coloring threshold voltage Vc (E2), and a decoloring threshold voltage Vd (E2) And an electrochromic composition E3 having a color developing threshold voltage Vc (E3) and a decoloring threshold voltage Vd (E3). Here, Vc (E1)> Vc (E2)> Vc (E3) and Vd (E1) <Vd (E2) <Vd (E3).
When a voltage value Vc1 satisfying Vc1 ≧ Vc (E1) is applied to the display element, all of the electrochromic compositions E1, E2, and E3 are colored. Next, when a voltage value Vc2 satisfying Vd (E1) <Vd2 ≦ Vd (E2) is applied, only E2 and E3 are decolored. Therefore, only E1 can be selectively colored. Further, when a voltage value Vc2 satisfying Vc (E1)> Vc2 ≧ Vc (E2) is applied, E2 and E3 are colored. Next, when a voltage value Vc2 satisfying Vd (E2) <Vd3 ≦ Vd (E3) is applied, only E3 is decolored. Since E1 is not affected by this operation, only E2 can be selectively colored. Further, when a voltage value Vc3 satisfying Vc (E2)> Vc3 ≧ Vc (E3) is applied, E3 is colored and E1 and E2 are not affected. Therefore, all the electrochromic compositions can be independently developed by these multicolor display methods. In particular, if three types of electrochromic compositions that are yellow, magenta, and cyan are used in a colored state, full color display is possible.

Another feature of the multicolor display element of the present invention is that two or more types of electrochromic compositions E1, E2,... En (n is the number of types of electrochromic compositions) that develop different colors, respectively. When the threshold voltage for achieving the color development state is in the relationship of | Vc (E1) |> | Vc (E2) |>... | Vc (En) | The charge amount Qc is a combination having a relationship of | Qc (E1) |> | Qc (E2) |>...> | Qc (En) |. If a sufficient voltage is not applied to the device, only a part of the electrochromic composition is colored, but if a higher voltage is applied, other electrochromic compositions having different colors can be colored. Further, multicolor display can be performed by erasing only a part of the electrochromic composition that is colored by controlling the amount of injected charge from the state where the whole or part of the electrochromic composition is colored. An example of the multicolor display method is shown below.
An electrochromic composition A having a high color development threshold voltage on the display electrode as a display layer and a large charge amount necessary for decoloring, and an electrochromic composition B having a low color development threshold voltage and a small charge amount necessary for decolorization There is a configuration in which are stacked. When a voltage not lower than the coloring threshold voltage of the electrochromic composition B and lower than the coloring threshold voltage of the electrochromic composition A is applied to the display layer, only the electrochromic composition B develops color. Further, when a voltage equal to or higher than the coloring threshold voltage of the electrochromic composition A is applied, both the electrochromic compositions A and B are colored. From here, when a voltage opposite to the color development is applied for decoloring, if the amount of charge necessary for decoloring of composition B is sufficiently smaller than the amount of charge necessary for decoloring of composition A, the composition Only the product B can be erased and only the composition A can be developed. In this way, the electrochromic compositions A and B can be independently developed. Furthermore, if both the electrochromic compositions A and B are colored, the mixed color of the electrochromic compositions A and B can be displayed.
The above is an example of a multicolor display method using two types of electrochromic compositions, but multicolor display can be performed by the same method even in the case of three or more types. In particular, if three types of electrochromic compositions that are yellow, magenta, and cyan are used in a colored state, full color display is possible.

  Another feature of the multicolor display element of the present invention is that two or more types of electrochromic compositions E1, E2,... En (n is the number of types of electrochromic compositions) that develop different colors are colored. The charge amount Qc ′ required for decoloring is | Qc ′ when the charge amount Qc required for the above is in the relationship of | Qc (E1) |> | Qc (E2) |>. (E1) |> | Qc ′ (E2) |>...> | Qc ′ (En) | If a sufficient charge is not injected into the device, only a part of the electrochromic composition develops color. However, if a sufficient amount of charge is injected, other electrochromic compositions having different colors can be developed. Further, multicolor display is possible by erasing only a part of the electrochromic composition that has developed color by controlling the amount of injected charge for decoloring from the state in which the entire or part of the electrochromic composition has been developed. The charge referred to in the present invention is determined to be positive or negative depending on the structure of the element and depending on whether the color is developed or erased.

An example of the multicolor display method is shown below. Electrochromic composition A having a large amount of charge necessary for color development and a large amount of charge necessary for decolorization on the display electrode as a display layer, and a small amount of charge necessary for color development and a small amount of charge necessary for decolorization There is a configuration in which the electrochromic composition B is laminated. When a certain voltage is applied to the display layer in an amount necessary for the color development of the electrochromic composition B, only B develops color, and when a sufficient charge is applied to the electrochromic composition A, both A and B develop color. It becomes a state. From this point, when an amount of charge necessary for erasing the electrochromic composition B is applied, only B is decolored and only A is colored. If a sufficient charge is applied from here for erasing A, both A and B return to the erasing state.
The above is an example of a multicolor display method using two types of electrochromic compositions, but multicolor display can be performed by the same method even in the case of three or more types. In particular, if three types of electrochromic compositions that are yellow, magenta, and cyan are used in a colored state, full color display is possible.

The electrochromic composition of the present invention is characterized by comprising conductive or semiconductive fine particles carrying an organic electrochromic compound. Specifically, it is a composition structure in which an organic electrochromic compound having a polar group such as a phosphonyl group, a hydroxyl group or a carboxyl group is adsorbed on the surface of a fine particle having a particle diameter of about 5 nm to 50 nm. The composition develops a color when charges are transferred from the electrode-attached substrate through the fine particles to the organic electrochromic compound (decolored by reverse movement). Therefore, it is possible to change the threshold voltage for charge transfer due to differences in the conductive characteristics of the fine particles, differences in the interface portion between the fine particles and the organic electrochromic compound, and the like. In addition, various molecules can be designed by using an organic compound as the electrochromic compound. By changing the conjugate structure from the interface site to the chromophore site, the electron mobility can be controlled and the amount of charge required for color development can be changed. Moreover, various colors can be developed by the chromophore structure.
Therefore, electrochromic compositions having different colors, threshold voltages, and required charges can be produced by combining conductive or semiconductive fine particles having different conductive characteristics with organic electrochromic compounds having different colors and required charges.

  Another feature of the electrochromic composition of the present invention is that a conductive or semiconductive fine particle particle surface is modified to change its conductive properties. As described above, the threshold voltage of the coloring reaction and decoloring reaction of the organic electrochromic compound can be changed according to the difference in the conductive characteristics of the fine particles. At this time, if another atom, molecule, compound, or the like is modified on the surface of the fine particle, the conductive property of the fine particle is changed. For example, metal oxide fine particles such as titanium oxide fine particles can be easily coated on the surface with other metal oxides (aluminum oxide, silicon oxide, zirconium oxide, etc.) using a sol-gel method or the like. When this surface modification method is used, the conductive properties of the particles can be easily controlled by the type and amount of the molecule modified on the surface, which is effective in controlling the color development / decoloration threshold voltage.

  Another feature of the multicolor display element of the present invention is that a display layer made of an electrochromic composition is formed in an arbitrary pattern. In the multicolor display element of the present invention, even when a display layer is provided on the entire surface of a substrate with a transparent electrode, only a part of the color can be developed by applying a voltage, but the charge is slightly diffused. Therefore, the color image may be slightly blurred. Therefore, by patterning the display layer with high definition for each pixel in advance, it is possible to prevent blurring of the image due to charge diffusion and to obtain a sharp colored image.

Another feature of the multicolor display element of the present invention is that a white reflective layer is provided. Since the display layer of the multicolor display element of the present invention undergoes a reversible color change between the transparent state and the colored state, when it is a reflective display element, the whiteness of the element is determined by the characteristics of the white reflective layer. . If a white reflective layer in which white particles are dispersed in a resin or the like is used, the reflective layer can be easily produced and a high white reflectance similar to that of paper can be obtained.
As another method for obtaining a high white reflectance, there is a method in which pigment fine particles are dispersed in an electrolytic solution. The pigment fine particles are dispersed in advance in the electrolytic solution and then injected into the display element. In this method, since no resin for fixing the pigment fine particles is required, the conductivity in the element is good and the element can be driven at a low voltage. As the pigment fine particles, particles made of a general metal oxide can be applied as described above, and specific examples include titanium oxide, aluminum oxide, zinc oxide, silicon oxide, cesium oxide, yttrium oxide and the like.

  Another feature of the multicolor display element of the present invention is that it can be driven actively. Control using an active drive element is indispensable for high-definition display on an A4 size screen. In the multicolor display element of the present invention, active driving can be easily performed by providing an active driving element on the counter electrode.

Hereinafter, the present invention will be described in detail by way of examples.
Example 1
Examples of organic electrochromic compounds include 1-Benzl-1 ′-(2-phosphonoethyl) -4, 4′-bipyridinium dibromide (hereinafter referred to as EC1), and 1-Ethyl-1 ′-(3-phosphonopropyl)- Using 4,4′-bipyridinium dichloride (hereinafter referred to as EC2), EC1 was dissolved in water and EC2 was dissolved in ethanol to prepare respective 0.02M solutions. Next, about 20 wt% of titanium oxide fine particles having a primary particle diameter of 6 nm are added to the EC1 aqueous solution and about 30 wt% of the zirconium oxide fine particles having a primary particle diameter of 30 nm are added to the ethanol solution of EC2, respectively. Was adsorbed. A small amount of surfactant was added to each dispersion.
The display electrode was produced as follows. First, a titanium oxide fine particle dispersion liquid in which EC1 is adhered is applied to a part (area 1 cm 2 ) of a glass substrate having a tin oxide transparent electrode film on the entire surface by spin coating so as to have a thickness of about 2 μm. Heat at 24 ° C. for 24 hours. Next, a zirconium oxide fine particle dispersion liquid in which EC2 was adhered on the fine particle film was applied by spin coating so as to have a thickness of about 2 μm, and heated at 150 ° C. for 24 hours. The produced film was transparent.
The counter electrode was produced as follows. 5 g of titanium oxide particles having a primary particle size of 300 nm and 1 g of polyethylene resin were dispersed in 10 ml of a tetrahydrofuran solution. A dispersion prepared on a zinc plate having a thickness of 0.2 mm was applied to the entire surface by spin coating. The film thickness was about 5 microns and showed the same white color as paper.
The display electrode and the counter electrode were bonded together through a 50 μm spacer to produce a cell. An electrolyte solution in which 0.2 M of lithium perchlorate was dissolved in propylene carbonate was prepared, and sealed in this cell to produce a reflective multicolor display element.
When the white reflectance was measured without applying a voltage, it showed a high value of about 60%. In addition, this measurement was performed by irradiating diffused light using a spectrocolorimeter.
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a charge of 20 mC was applied at a voltage of 2.0 V, only a portion of the fine particle layer of the display electrode developed reddish purple. This color is due to the development of EC1. With this charge amount, EC2 did not develop color. When a voltage of −3.0 V was sufficiently applied, the reddish purple color disappeared and became white again.

(Example 2)
When the display electrode was connected to the negative electrode and the counter electrode was connected to the positive electrode, and a charge of 50 mC was applied at a voltage of 2.0 V, only a portion of the fine particle layer of the display electrode was colored dark purple. This color is due to the fact that both EC1 and EC2 are colored. When a voltage of −3.0 V was sufficiently applied, the reddish purple color disappeared and became white again.

(Example 3)
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a charge of 50 mC was applied at a voltage of 3.0 V, only a portion of the fine particle layer of the display electrode was colored dark purple. When a voltage of -1.0 V was applied for a short time from this state, the color changed from dark purple to blue. This is because EC1 is decolored and EC2 color is visible. When a voltage of −3.0 V was sufficiently applied, the blue color disappeared and became white again.

Example 4
As an organic electrochromic compound, EC1 and 1-Ethyl-1 ′-(2-phosphonoethyl) -4,4′-bipyridinium dichloride (hereinafter referred to as EC3) are used, EC1 in water and EC3 in ethanol. Dissolve to prepare each 0.02M solution. Next, about 20 wt% of titanium oxide fine particles having a primary particle diameter of 6 nm are added to the EC1 aqueous solution, and about 20 wt% of the zirconium oxide fine particles having a primary particle diameter of 30 nm are added to the ethanol solution of EC3, and the organic electrochromic compound is dispersed on the surface of the fine particles. Was adsorbed. A small amount of surfactant was added to each dispersion.
The display electrode was produced as follows. First, a titanium oxide fine particle dispersion liquid in which EC1 is adhered is applied to a part (area 1 cm 2 ) of a glass substrate having a tin oxide transparent electrode film on the entire surface by spin coating so as to have a thickness of about 2 μm. Heat at 24 ° C. for 24 hours. Next, a zirconium oxide fine particle dispersion liquid in which EC3 was adhered on the fine particle film was applied by spin coating so as to have a thickness of about 2 μm, and heated at 150 ° C. for 24 hours. The produced film was transparent.
The counter electrode was produced as follows. 5 g of titanium oxide particles having a primary particle size of 300 nm and 1 g of polyethylene resin were dispersed in 10 ml of a tetrahydrofuran solution. A dispersion prepared on a zinc plate having a thickness of 0.2 mm was applied to the entire surface by spin coating. The film thickness was about 5 microns and showed the same white color as paper.
The display electrode and the counter electrode were bonded together through a 50 μm spacer to produce a cell. An electrolyte solution in which 0.2 M of lithium perchlorate was dissolved in propylene carbonate was prepared, and sealed in this cell to produce a reflective multicolor display element.
When the white reflectance was measured without applying a voltage, it showed a high value of about 60%. In addition, this measurement was performed by irradiating diffused light using a spectrocolorimeter.
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a voltage of 1.0 V was sufficiently applied, only a portion of the display electrode having a fine particle layer developed reddish purple. This color is due to the development of EC1. EC3 did not develop color at this applied voltage. When a voltage of −3.0 V was sufficiently applied, the reddish purple color disappeared and became white again.

(Example 5)
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a voltage of 3.0 V was sufficiently applied, only a portion having the fine particle layer of the display electrode was colored deep purple. This color is attributed to the development of EC1 and EC3. When a voltage of −3.0 V was sufficiently applied, the deep purple color disappeared and became white again.

(Example 6)
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a voltage of 3.0 V was sufficiently applied, only a portion having the fine particle layer of the display electrode was colored deep purple. Next, when a voltage of −1.0 V was sufficiently applied, only a portion where the fine particle layer of the display electrode was changed to blue. This color is caused by the fact that only EC1 is erased from the state where both EC1 and EC3 are colored and the electrochromic EC3 color remains. When a voltage of −3.0 V was sufficiently applied, the blue color disappeared and became white.

(Example 7)
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a voltage of 3.0 V was sufficiently applied, only a portion having the fine particle layer of the display electrode was colored deep purple. Next, when a voltage of −1.0 V was sufficiently applied, only a portion where the fine particle layer of the display electrode was changed to blue. This color is caused by the fact that only EC1 is erased from the state where both EC1 and EC3 are colored and the electrochromic EC3 color remains. Further, when a voltage of 1.0 V was applied to a part of the blue colored portion, EC1 was colored again, and this portion was changed to dark purple. When a voltage of −3.0 V was sufficiently applied, everything was decolored and turned white.

(Example 8)
When the display electrode was connected to the negative electrode and the counter electrode was connected to the positive electrode, and a charge of 30 mC was applied at a voltage of 1.0 V, only a portion of the fine particle layer of the display electrode was colored reddish purple. This color is due to the development of EC1. EC3 did not develop color at this applied voltage. When a voltage of −3.0 V was sufficiently applied, the reddish purple color disappeared and became white again.

Example 9
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a charge of 10 mC was applied at a voltage of 3.0 V, only a portion of the fine particle layer of the display electrode was colored blue. This color is due to the development of EC3. With this charge amount, EC1 hardly developed color. When a voltage of −3.0 V was sufficiently applied, the blue color disappeared and became white again.

(Example 10)
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a charge of 50 mC was applied at a voltage of 3.0 V, only a portion of the fine particle layer of the display electrode was colored dark purple. This color is caused by the development of both EC1 and EC3. When a voltage of −3.0 V was sufficiently applied, the deep purple color disappeared and became white again.

(Example 11)
As organic electrochromic compound, with EC1, and EC2, EC1 in water, EC 2 is dissolved in ethanol, and the respective 0.02M solutions were prepared. Next, titanium oxide fine particles having a primary particle size of 6 nm are used in the EC1 aqueous solution, and particles having aluminum oxide and zirconium oxide coated on the surface of the titanium oxide fine particles having a primary particle size of 6 nm are used in the ethanol solution of EC2. In addition, the mixture was dispersed to adsorb the organic electrochromic compound on the surface of the fine particles. A small amount of surfactant was added to each dispersion.
The display electrode was produced as follows. First, a titanium oxide fine particle dispersion liquid in which EC1 is adhered is applied to a part (area 1 cm 2 ) of a glass substrate having a tin oxide transparent electrode film on the entire surface by spin coating so as to have a thickness of about 2 μm. Heat at 24 ° C. for 24 hours. Next, a surface-modified titanium oxide fine particle dispersion liquid in which EC2 was adhered on this fine particle film was applied by spin coating so as to have a thickness of about 2 μm, and heated at 150 ° C. for 24 hours. The produced film was transparent.
The counter electrode was produced as follows. An aqueous solution containing 40 wt% of tin oxide fine particles with a primary particle size of 30 nm is applied to a glass substrate with a tin oxide transparent electrode film on the entire surface to a thickness of about 2 μm by spin coating, and baked at 450 ° C. for 1 hour. I concluded.
The display electrode and the counter electrode were bonded to each other through a 75 μm spacer to produce a cell. An electrolytic solution in which 50 wt% of titanium oxide particles with a primary particle size of 300 nm are dispersed in a solution of 0.2 M lithium perchlorate dissolved in propylene carbonate is prepared and enclosed in this cell to produce a reflective multicolor display element. did.
When the white reflectance was measured without applying a voltage, it showed a high value of about 60%. In addition, this measurement was performed by irradiating diffused light using a spectrocolorimeter.

(Example 12)
When the display electrode was connected to the negative electrode, the counter electrode was connected to the positive electrode, and a voltage of 3.0 V was sufficiently applied, only a portion having the fine particle layer of the display electrode was colored deep purple. This color is caused by the fact that both EC1 and EC2 are colored. Next, when sufficient voltage of -1.5V was applied, only EC1 was decolored and turned blue. Further, when a voltage of −4.5 V was sufficiently applied, EC2 was also decolored and became white.

It is the figure which showed the example of the structure of the multicolor display element in this invention. It is the figure which showed the example of the combination of the coloring threshold voltage of a multicolor display element, and a decoloring threshold voltage. It is another figure which showed the example of the combination of the coloring threshold voltage of a multicolor display element, and a decoloring threshold voltage.

Claims (11)

  1. A display electrode, a counter electrode provided opposite to the display electrode at a distance from each other, and an electrolyte disposed between both electrodes, and develops different colors on the surface of the display electrode on the counter electrode side. And a multicolor display element having a display layer formed by laminating two or more types of electrochromic compositions having different charge amounts (mC / cm 2 ) required for color development to a sufficient color density ,
    The multi-color display element, wherein the two or more types of electrochromic compositions are conductive or semiconductive fine particles whose conductive characteristics are changed by attaching organic electrochromic compounds that develop different colors to the surface.
  2. A display electrode, a counter electrode provided opposite to the display electrode at a distance from each other, and an electrolyte disposed between both electrodes, and develops different colors on the surface of the display electrode on the counter electrode side. And two or more different at least one of a threshold voltage for entering a color developing state, a threshold voltage for entering a decoloring state, or a necessary charge amount (mC / cm 2 ) for developing a sufficient color density Having a display layer formed by laminating the electrochromic composition of
    Two or more types of electrochromic compositions E1, E2,... En (where n is the number of types of electrochromic compositions) that develop different colors have a threshold voltage of | Vc ( E1) |> | Vc (E2) |>...> | Vc (En) |, the required charge amount Qc for color development to a sufficient color density is | Qc (E1) | <| A multicolor display element characterized by being a combination having a relationship of Qc (E2) | <... <| Qc (En) |.
  3. A display electrode, a counter electrode provided opposite to the display electrode at a distance from each other, and an electrolyte disposed between both electrodes, and develops different colors on the surface of the display electrode on the counter electrode side. And two or more different at least one of a threshold voltage for entering a color developing state, a threshold voltage for entering a decoloring state, or a necessary charge amount (mC / cm 2 ) for developing a sufficient color density Having a display layer formed by laminating the electrochromic composition of
    Two or more types of electrochromic compositions E1, E2,..., En (n is the number of types of electrochromic compositions) that develop different colors are set to Vc (E1) , Vc (E2),... Vc (En), where Vd (E1), Vd (E2),... Vd (En) are Vc (E1)> A multi-color display element characterized by a combination having a relationship of Vc (E2)>..> Vc (En)> Vd (En)>..> Vd (E2)> Vd (E1).
  4.   The multicolor display element according to any one of claims 1 to 3, comprising three types of electrochromic compositions for coloring yellow, magenta, and cyan.
  5. 5. The reflective multicolor display element according to claim 2, wherein the electrochromic composition comprises conductive or semiconductive fine particles carrying an organic electrochromic compound.
  6.   6. The reflection type multi-layer according to claim 5, wherein a plurality of types of electrochromic compositions each carrying an organic electrochromic compound that develops different colors on conductive or semiconductive fine particles having different conductive properties are laminated. Color display element.
  7.   The reflective multicolor display element according to claim 6, wherein conductive or semiconductive fine particles whose conductive properties are changed by attaching an organic electrochemical compound to the surface are used.
  8.   The multicolor display element according to claim 1, wherein the display layer is formed in an arbitrary pattern.
  9.   9. The multicolor display element according to claim 1, wherein a white reflective layer is provided between the display electrode having the display layer and the counter electrode.
  10.   The display element according to claim 1, wherein the electrolyte contains fine pigment particles.
  11.   The multicolor display element according to claim 1, wherein a drive element is formed on the display electrode substrate or the counter electrode substrate.
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